Multiple switch float switch apparatus

Abstract

A float switch apparatus for controlling the energization of multiple electric circuits in response to the level of a liquid in a vessel, and a pump system incorporating same, are provided. The apparatus has a guide structure adapted to be mounted in a fixed position relative to the vessel. A first micro-switch with a normal and an engaged position is mounted to the guide structure and is adapted to be connected into a first electric circuit to control the energization thereof. A second microswitch with a normal and an engaged position is mounted to the guide structure at a location above the first micro-switch and is adapted to be connected into a second electric circuit to control the energization thereof. A float rod is slideably mounted to the guide structure for reciprocating movement in a generally vertical direction in a zone above a resting position. The float rod has upper and lower float stops and a lower cam surface for releasing the first micro-switch from an engaged position to its normal position during upward movement of the float rod above the resting position. The float rod also has an upper cam surface for moving the second micro-switch from its normal position to its engaged position during upward movement of the float rod. The float, adapted to float with the level of liquid in the vessel, is slideably mounted to the float rod between the upper and lower float stops.

The invention claimed is: 
     
       1. A method of operating a sump pump system having a power source, a primary electric motor connected to a primary pump operable to pump liquid from a vessel, a secondary electric motor connected to a secondary pump operable to pump liquid from the vessel a first switch operatively connected between the primary electric motor and the power source and a second switch operatively connected between the secondary electric motor and the power source, the method comprising the steps of:
 at a predetermined first liquid level in the vessel, closing the first switch to energize the primary pump motor, 
 at a predetermined second liquid level in the vessel higher than the first liquid level, opening the first switch to de-energize the primary pump motor, and, 
 at a predetermined third liquid level in the vessel higher than the second liquid level, closing the second switch to energize the secondary pump motor 
 
       wherein the said switches are incorporated into a system actuator having a float mechanism responsive to liquid level in the vessel and the method comprises the further step of controlling operation of said switches according to the position of the float mechanism, wherein the first and second switches are micro-switches having open and closed positions and the system actuator comprises a guide structure mounted in a fixed position relative to the vessel to which the first and second switches are mounted, a float rod slideably mounted to the guide structure allowing reciprocating movement in a generally vertical direction in an operating zone above a resting position, the float rod having upper and lower ends and upper and lower float stops and the float rod additionally having a first switch-closing cam surface cooperating with the first switch, a switch-opening cam surface cooperating with the first switch, and a second switch-closing cam surface cooperating with the second switch, and, a float slideably mounted to the float rod between the upper and lower float stops, which float floats with the level of liquid in the vessel, and wherein said controlling step comprises the steps of:
 moving the first switch from its open to its closed position by means of the first switch-closing cam surface during upward movement of the float rod; 
 moving the first switch from its closed to its open position by means of the switch-opening cam surface during further upward movement of the float rod; and, 
 moving the second switch from its open to its closed position by means of the second switch-closing cam surface during yet further upward movement of the float rod. 
 
     
     
       2. A method as claimed in  claim 1  wherein the first and second switches are normally-closed and the first and second switch-closing cam surfaces are shaped to release the first and second switches to their normal positions at predetermined points during upward movement of the float rod and such that, under the influence of gravity, the weight of the float rod is insufficient to allow the float rod to move downwardly against resistance provided either by the first switch or separately by the second switch and the weight of the float rod combined with at least a portion of the weight of the float is sufficient to overcome either such resistance and to move the float rod downwardly and wherein said controlling step comprises the further steps of:
 supporting the float rod in a fixed position by the interaction of the second switch and the second switch-closing cam surface during downward movement of the float in an upper zone; and 
 releasing the float rod to move downwardly when the weight of the float rod combined with at least a portion of the weight of the float exceeds a threshold and allowing the second switch-opening cam surface to operate in reverse to close the second switch. 
 
     
     
       3. A method as claimed in  claim 2  wherein said controlling step comprises the further steps of:
 supporting the float rod in a fixed position by the interaction of the first switch and the first switch-closing cam surface during downward movement of the float in a lower predetermined zone; and 
 releasing the float rod to move downwardly when the weight of the float rod combined with at least a portion of the weight of the float exceeds a threshold and allowing the first switch-opening cam surface to operate in reverse to close the first switch. 
 
     
     
       4. A method as claimed in  claim 1  wherein the first switch is normally-closed and the first switch-closing cam surface is shaped to release the first switch to its normal position at a predetermined point during upward movement of the float rod and such that, under the influence of gravity, the weight of the float rod is insufficient to allow the float rod to move downwardly against resistance provided by the first switch and the weight of the float rod combined with at least a portion of the weight of the float is sufficient to overcome such resistance and to move the float rod downwardly and wherein said controlling step comprises the further steps of:
 supporting the float rod in a fixed position by the interaction of the first switch and the first switch-closing cam surface during downward movement of the float in a predetermined zone; and 
 releasing the float rod to move downwardly when the weight of the float rod combined with at least a portion of the weight of the float exceeds a threshold and allowing the first switch-opening cam surface to operate in reverse to close the first switch. 
 
     
     
       5. A method of operating a sump pump system having a power source, a primary electric motor connected to a primary pump operable to pump liquid from a vessel, a secondary electric motor connected to a secondary pump operable to pump liquid from the vessel, a first switch operatively connected between the primary electric motor and the power source and a second switch operatively connected between the secondary electric motor and the power source, the method comprising the steps of:
 at a predetermined first liquid level in the vessel, closing the first switch to energize the primary pump motor, 
 at a predetermined second liquid level in the vessel higher than the first liquid level, opening the first switch to de-energize the primary pump motor, and, 
 at a predetermined third liquid level in the vessel higher than the second liquid level, closing the second switch to energize the secondary pump motor wherein the said switches are incorporated into a system actuator having a float mechanism responsive to liquid level in the vessel and the method comprises the further step of controlling operation of said switches according to the position of the float mechanism, 
 
       wherein the first and second switches are micro-switches having open and closed positions and the system actuator comprises a guide structure mounted in a fixed position relative to the vessel to which the first and second switches are mounted, a float rod slideably mounted to the guide structure allowing reciprocating movement in a generally vertical direction in an operating zone above a resting position, the float rod having upper and lower ends and upper and lower float stops and the float rod additionally having switch-closing cam surface structure for actuating the first and second switches and a switch-opening cam surface cooperating with the first switch, and, a float slideably mounted to the float rod between the upper and lower float stops, which float floats with the level of liquid in the vessel, and wherein said controlling step comprises the steps of:
 moving the first switch from its open to its closed position by means of the switch-closing cam surface structure during upward movement of the float rod; 
 moving the first switch from its closed to its open position by means of the switch-opening cam surface during further upward movement of the float rod; and, 
 moving the second switch from its open to its closed position by means of the switch-closing cam surface structure during yet further upward movement of the float rod. 
 
     
     
       6. A method as claimed in  claim 5  wherein the switch-closing cam surface structure comprises a first switch-closing cam surface cooperating with the first switch and a second switch-closing cam surface cooperating with the second switch and wherein said step of moving the first switch from its open to its closed position comprises moving the first switch by means of the first switch-closing cam surface; and, said step of moving the second switch from its open to its closed position comprises moving the second switch by means of the second switch-closing cam surface. 
     
     
       7. A switching apparatus for controlling the operation of two electrical pump motors, in response to the level of a liquid in a vessel, the apparatus comprising:
 a first switch adapted to be connected to control the operation of a first electrical pump motor; 
 a second switch adapted to be connected to control the operation of a second electrical pump motor; 
 a liquid level responsive apparatus operatively connected to the first and second switches to control the operation thereof whereby, at a first predetermined level the liquid level responsive apparatus will close the first switch, at a second predetermined level higher than the first level the liquid level responsive apparatus will open the first switch, and at a third predetermined level higher than the second level the liquid level responsive apparatus will close the second switch; 
 a guide structure adapted to be mounted in a fixed position relative to the vessel and wherein the switches are attached to the guide structure, 
 
       wherein the liquid level responsive apparatus comprises a float mechanism attached to the guide structure and mechanically associated with the first and second switches, 
       wherein the first and second switches are micro-switches having open and closed positions and the float mechanism comprises:
 a float rod slideably mounted to the guide structure allowing reciprocating movement in a generally vertical direction in an operating zone above a resting position, the float rod having upper and lower ends and upper and lower float stops and the float rod additionally having a first switch-closing cam surface cooperating with the first switch to move the first switch from its open to its closed position during upward movement of the float rod, a switch-opening cam surface cooperating with the first switch to move the first switch from its closed to its open position during further upward movement of the float rod, and a second switch-closing cam surface cooperating with the second switch to move the second switch from its open to its closed position during yet further upward movement of the float rod, and, 
 a float slideably mounted to the float rod between the upper and lower float stops, which float floats with the level of liquid in the vessel. 
 
     
     
       8. An apparatus as claimed in  claim 7  wherein the first and second switches are normally-closed and the first and second switch-closing cam surfaces are shaped to release the first and second switches to their normal positions at predetermined points during upward movement of the float rod and such that, under the influence of gravity, the weight of the float rod is insufficient to allow the float rod to move downwardly against resistance provided either by the first switch or separately by the second switch and the weight of the float rod combined with at least a portion of the weight of the float is sufficient to overcome either such resistance and to move the float rod downwardly. 
     
     
       9. An apparatus as claimed in  claim 7  wherein the first switch is normally-closed and the first switch-closing cam surface is shaped to release the first switch to its normal position at a predetermined point during upward movement of the float rod and such that, under the influence of gravity, the weight of the float rod is insufficient to allow the float rod to move downwardly against resistance provided by the first switch and the weight of the float rod combined with at least a portion of the weight of the float is sufficient to overcome such resistance and to move the float rod downwardly. 
     
     
       10. A switching apparatus for controlling the operation of two electrical pump motors, in response to the level of a liquid in a vessel, the apparatus comprising:
 a first switch adapted to be connected to control the operation of a first electrical pump motor; 
 a second switch adapted to be connected to control the operation of a second electrical pump motor; 
 a liquid level responsive apparatus operatively connected to the first and second switches to control the operation thereof whereby at a first predetermined level the liquid level responsive apparatus will close the first switch, at a second predetermined level higher than the first level the liquid level responsive apparatus will open the first switch, and at a third predetermined level higher than the second level the liquid level responsive apparatus will close the second switch, 
 a guide structure adapted to be mounted in a fixed position relative to the vessel and wherein the switches are attached to the guide structure, 
 
       wherein the liquid level responsive apparatus comprises a float mechanism attached to the guide structure and mechanically associated with the first and second switches, 
       wherein the first and second switches are micro-switches having open and closed positions and the float mechanism comprises:
 a float rod slideably mounted to the guide structure allowing reciprocating movement in a generally vertical direction in an operating zone above a resting position, the float rod having upper and lower ends and upper and lower float stops and the float rod additionally having switch-closing cam surface structure cooperating with the first switch to move the first switch from its open to its closed position during upward movement of the float rod, a switch-opening cam surface cooperating with the first switch to move the first switch from its closed to its open position during further upward movement of the float rod, the switch-closing cam surface structure additionally cooperating with the second switch to move the second switch from its open to its closed position during yet further upward movement of the float rod, and, 
 a float slideably mounted to the float rod between the upper and lower float stops, which float floats with the level of liquid in the vessel. 
 
     
     
       11. An apparatus as claimed in  claim 10  wherein the switch-closing cam surface structure comprises a first switch-closing cam surface cooperating with the first switch and a second switch-closing cam surface cooperating with the second switch. 
     
     
       12. A pump systems for pumping liquid from a vessel and operating a secondary pump associated therewith comprising:
 a power source; 
 a primary electric motor connected to a primary pump operable to pump liquid from the vessel; 
 a secondary electric motor connected to a secondary pump operable to pump liquid from the vessel; 
 a first switch operatively connected between the primary electric motor and the power source; 
 a second switch operatively connected between the secondary electric motor and the power source; 
 liquid level responsive apparatus operatively connected to the first and second switches to control the operation thereof whereby at a first predetermined level the liquid level responsive apparatus will close the first switch, at a second predetermined level higher than the first level the liquid level responsive apparatus will open the first switch, and at a third predetermined level higher than the second level the liquid level responsive apparatus will close the second switch; 
 a guide structure mounted in a fixed position relative to the vessel and wherein the switches are attached to the guide structure, 
 
       wherein the liquid level responsive apparatus comprises a float mechanism attached to the guide structure and mechanically associated with the first and second switches, 
       wherein the first and second switches are micro-switches having open and closed positions and the float mechanism comprises:
 a float rod slideably mounted to the guide structure allowing reciprocating movement in a generally vertical direction in an operating zone above a resting position, the float rod having upper and lower ends and upper and lower float stops and the float rod additionally having a first switch-closing cam surface cooperating with the first switch to move the first switch from its open to its closed position during upward movement of the float rod, a switch-opening cam surface cooperating with the first switch to move the first switch from its closed to its open position during further upward movement of the float rod, and a second switch-closing cam surface cooperating with the second switch to move the second switch from its open to its closed position during yet further upward movement of the float rod, and, 
 a float slideably mounted to the float rod between the upper and lower float stops, which float floats with the level of liquid in the vessel. 
 
     
     
       13. A system as claimed in  claim 12  wherein the first and second switches are normally-closed and the first and second switch-closing cam surfaces are shaped to release the first and second switches to their normal positions at predetermined points during upward movement of the float rod and such that, under the influence, of gravity, the weight of the float rod is insufficient to allow the float rod to move downwardly against resistance provided either by the first switch or separately by the second switch and the weight of the float rod combined with at least a portion of the weight of the float is sufficient to overcome either such resistance and to move the float rod downwardly. 
     
     
       14. A system as claimed in  claim 12  wherein the first switch is normally-closed and the first switch-closing cam surface is shaped to release the first switch to its normal position at a predetermined point during upward movement of the float rod and such that, under the influence of gravity, the weight of the float rod is insufficient to allow the float rod to move downwardly against resistance provided by the first switch and the weight of the float rod combined with at least a portion of the weight of the float is sufficient to overcome such resistance and to move the float rod downwardly. 
     
     
       15. A pump system for pumping liquid from a vessel and operating a secondary pump associated therewith comprising:
 a power source; 
 a primary electric motor connected to a primary pump operable to pump liquid from the vessel; 
 a secondary electric motor connected to a secondary pump operable to pump liquid from the vessel; 
 a first switch operatively connected between the primary electric motor and the power source; 
 a second switch operatively connected between the secondary electric motor and the power source; 
 a liquid level responsive apparatus operatively connected to the first and second switches to control the operation thereof whereby at a first predetermined level the liquid level responsive apparatus will close the first switch, at a second predetermined level higher than the first level the liquid level responsive apparatus will open the first switch, and at a third predetermined level higher than the second level the liquid level responsive apparatus will close the second switch; 
 a wide structure mounted in a fixed position relative to the vessel and wherein the switches are attached to the guide structure, 
 
       wherein the liquid level responsive apparatus comprises a float mechanism attached to the guide structure and mechanically associated with the first and second switches, 
       wherein the first and second switches are micro-switches having open and closed positions and the float mechanism comprises:
 a float rod slideably mounted to the guide structure allowing reciprocating movement in a generally vertical direction in an operating zone above a resting position, the float rod having upper and lower ends and upper and lower float stops and the float rod additionally having switch-closing cam surface structure cooperating with the first switch to move the first switch from its open to its closed position during upward movement of the float rod, a switch-opening cam surface cooperating with the first switch to move the first switch from its closed to its open position during further upward movement of the float rod, the switch-closing cam surface structure additionally cooperating with the second switch to move the second switch from its open to its closed position during yet further upward movement of the float rod, and, 
 a float slideably mounted to the float rod between the upper and lower float stops, which float floats with the level of liquid in the vessel. 
 
     
     
       16. A system as claimed in  claim 15  wherein the switch-closing cam surface structure comprises a first switch-closing cam surface cooperating with the first switch and a second switch-closing cam surface cooperating with the second switch.